(() => {
    class Person {
        constructor(firstName, lastName) {
            this.firstName = firstName;
            this.lastName = lastName;
            this.fullName = this.firstName + "_" + this.lastName;
        }
        showFullName() {
            console.log(this.fullName);
        }
    }
    function showFullName(p) {
        return p.firstName + '__' + p.lastName;
    }
    const p = new Person('诸葛', '孔明');
    p.showFullName();
    let name = showFullName(p);
    console.log(name);
})();
